Magnetic fluid mixture clutch with plow



July 29, 1952 M. P. WINTHER ETAL MAGNETIC FLUID MIXTURE CLUTCH WITH PLOW4 Sheets-Sheet 1 Filed Jan. 21, 1949 July 29, 1952 M. P. WINTHER EI'AL2,604,954

MAGNETIC FLUID MIXTURE CLUTCH WITH PLOW 4 Sheets-Sheet 2 Filed Jan. 21,1949 F|G.5. 1;: \q

5/ 37 I F 57 Tit July 29, 1952 M. P. WINTHER ETAL MAGNETIC FLUID MIXTURECLUTCH WITH PLOW 4 Sheets-Sheet 3 Filed Jan. 21, 1949 u y 29, 1952 M. P.WINTHER EI'AL 2,604,964

MAGNETIC FLUID MIXTURE CLUTCH WITH PLOW Filed Jan. 21, 1949 4Sheets-Sheet 4 Patented July 29, 1952' UNITED? STATES PATENT oFFicsMAGNETIC FLUID MIXTURE CLUTCH WITH PLOW Martini. Winther,

Application-Ianuary 21-, 1949. Serial No. 11,344.-

This invention. relates generally todynamoelectric. machines, and; with.regard to. certain more specific features. to electric clutches.employing agranular magnetic coupling material,

Amongthe several obj ectsof the invention may be-notedthe provisionofan. electric, clutch having; an improved granular magnetic.materialincorporating better qualities of distribution-whereby betterdynamic balance is assuredunder all operating conditions; the provisionof a clutch of the class described'incorporating means for con.-

trolling, the: distribution of the magnetic mate.- rial; to: obtainoptimum: running and idling. con.- ditions without undesirable drag in.the case of the; latter; the. provision. of a clutch-of thisjclass in.which the magnetic material. may more easily be retained and. in whichexcessive churning is avoided;- and the provision of a clutch of thisclass in which the magnetic material is of amore permanent; nature.Otherobjects will be in part apparent and in part pointed outhereinafter.

The invention accordingly comprisesthe elements: and" combinations ofelements, features of construction, and arrangements or parts which willbe exemplified in the structures hereinafter described; and the scope ofthe application of whichwill be-indicated in the following claims.

In the accompanying drawings, in which several of: various; possibleembodiments of the in,- vention are illustrated,

Fig. 1 is a fragmentary longitudinal section of 21 Claims. (aims-21.5),1

a clutch embodying one. form of' the invention and viewed on line l--l;of Fig.v 2;

Fig; 2 is a developedplan viewof several, poles as viewed from thesection line 27-2 in Fig. 1:;

Fig; 3. is a fragmentary'd'etail section taken on line 3-3 of Fig. 1

Figs. 4-6 are views corresponding to Figs; 1-3

respectively, showing an alternative embodiment of the invention; inwhich Fig; 4 is viewed substantially on line 4-4 of. Fig. 5; Fig.j5'-isviewe,d

.21. "'1 there is. shown .at. numeral, If what. may. e equisideredinitially as a driving element to which is bolted-a hub. 3; of. a fieldmemberg Hub-3 iscomposed of a magnetic material. Carried .onlfthe hubis. an annular field coil 5, embraced, onopposite. sides by magneticrings [and 9, which are fastened to the hub 3. Ring 1 is. inv directcontact with-the. hub while. a nonmagnetic band. I'll. isinterposed..be,tween -the.'ring. land. the hub; pro.- viding. a magneticgap. 'I'hepurpose, oi; thisgwill appear. Extending from the ringsandembraciii the coil..5. are interdigitated'polerforming teeth-543.,

theinner faces, or which. lie adjacent. the. coiland the outer faces ofWhichli'efin or near an ma .inary external-cylinder, as. indicatedinIE'igs "1 and 3. I At numeral. .l.5.lis,iwhat. may be. referred toinitially as .adrive'n shaft between which and the. hub3Lis..a,.pilot.bearing.1.1.. Attached to. the shaft- I5 is asupjportingspider 9, t0. the outside of. whichis attachedarotor 2]., iormi'ng asmooth interior. finductorgsurf ace lying n. y inde slightly: larger,than theimagi'nary cylinder which embraces. the. outer. faces, of fthe'poles; [3; "The rotor 2| is, magnetic.at;leas tin the portionsoppjjdsite. the poles IS... in a. machine .of the orderjgf severalfeetin diameter, the. resulting gan between-the. pole endsandthe insideof the inductor 2|- is of. theorden of. .020. inch as, indicated 5 1C-At-numerals. 23 are.. shown. labyrinth. runnin seals.. Theinner e ements2.2. of; these seals ar fastened to the rin s. 1 and. 9.,.,re ne tie1y-, The outer element 2.4. of. 0. 1. eek formed. in the spider laandthe. cuter lementii of. theothgr seal. is boltedto. the..ind1.1.Q Q.-2.L. as. n ed" a 25. Themembers .22... 2.4.2. m ng h bx th seals arepreferably onmag eti Br x t thecoil 5., atoroidal fluggfieldenvelopesit,',pas;s'ing substantially on line 5-5 of: Fig. 4; and Fig. Bis.

viewed substantially on line 6-6 of Fig. 4;

Figs. 79 are views similar to Figs. 46 respectively, showing anotherembodiment; in which Fig. 7: isviewed on line T-J of Fig. 8; Fig. 8 isviewed online 8.-8 ofFi'g; 7; and Fig. 9 is viewed Orr line; 9--9' ofFig. 7; and,

Figs; 1.0-12 are views similar to Figs. 7-9 respectively, showinganother embodiment; in

.which Fig. 10 isviewed on line l-0-|0 of Fig. 11;

Fig. L1 is viewed on line HH of Fig; 10; and.

Fig. 12 is viewed on line l2-l2 of Fig. 10.

Similar reference characters, indicate corresponding parts throughoutthe several views of the drawings.

Referring now more-particularly to Figs. 1-3,. I

thronghth .11 115551...it te fl an 2 I g the .in cluctcr Then if eithermember I or IE is driven th'e other will! follow, due tomagnetomotivereactions between the magnetic poles formedat the teeth I3. and. the. re ctive magnetic fie d-f om e dy currents which. are.induced in the, inductor 21. Apurelyeddy-cur e slipjc i pl na f e abovedescribed. nature operates with 'someslip; thatis, it cannot be broughtto, complete synchronism because some relative. rotationisnecessarylbetween the. field and in uctor. memb s in. o d to. obtain.the eddy currents nece sary I her active. ma netism.

- In order. to. bring. aboutcomplet synchron when coil 5 issufllcientlyenergized. we. provide within the inductor 2| a mass of .lpreferablysemisolid (not liquidnor solid) magnetic material 21. That is,-material. 27 is not only nQnsQlid built. is preferably semisolid...- Asuitable mate... 'al. i a

meric organic silicon compound such as one of the silicones(organosiloxanes), with a waterinsoluble soap base. A typicalsatisfactory sili- I cone grease is one manufactured by the Dow CorningCorporation, identified as DC 44, which at a fairly constant viscositywill withstand wide temperature variations, being practicallynonvolatile and highly resistant to hardening. A satisfactory ratio byweight of the stated iron particles to the stated type of grease may be,for example, 3:1. Such a material is semisolid, having aconsistency suchthat it will cling to a verticaljorinvertedsurfacefor long periods oftime without flowing. Moreover, it is not tacky; Its semisolidcharacteristics are similar to those of household petroleum .jelly.

f A quantity of the stated introduced into the chamber formed by theinductor 2,l.around the poles 13.1 This chamber iscjarried out laterallytoform'side channels 29.

magnetic semisolid is w "The semisolid may either take up a position.ra-

dially bridging the gap 0, or a substantial amount of the grease may beforced from the gap into thephannels 29. In order mechanically 'to con--trol the positioning of the grease 21, two approximatelyopposite membersof the poles l 3 are promesa with V'-shaped or chevron-shaped raisedsurfaces such as shown at 3|, whichact as plows or 'scrapers, Thus,assuming that the coil '5 is uriexcitedipoles l3 and inductor 2 demagne-.tized) any relative motion of the poles l3 .relative to the inductor 2|in the directionof the arjrow in Fig. 2 will result in the plows orscrapers 3.l plowing the semisolid out of the/gap C. This "isillustrated in, Fig. '1, wherein the semisolidhas been -thrown out intoridges in the spaces 29. Thesemisolidmay be drawn into the gap, evenagainst the plowing-out action, by sufiiciently exciting coil 5. Thismagnetizes the semisolid, drawing it into the gap C. Here it functionsto transmit torque between opposite faces of the gap.- This is assistedby the magnetic reactions from the eddy currents induced in the member2| An'. important feature of the invention is the semisolid property ofthe material 21 which tends fairly well to maintain any positionintowhich it is pushed, without displacement by flowing under its owngravitational weight. Being semi- .solid, it can be pushed'out of thegap by the plowing action, and pulled -,inlby the magnetic field ,but ifleft alone will substantially maintain a position; 7 o

Operation is as follows, assumingat the start i that the coil isdeenergized and that the grease is in the general initial position shownin Fig. 1. In this position the grease has been plowed out of the gap Cand lies in the stated self-sustaining ridges in the channels 29. If newa prime mover connected with the driver 1 be started, the new membersconstituted by the parts 3, 5. i, 9 x and I3 may rotate freely becauseof the gap theretofore caused by the plows 3| between the grease and thepole ends. Thus idling may occur with substantially no, drag, exceptpossibly a slight amount of windage, between the driving and drivenmembers i and i5. I

"If now the coil 5 be energized, there will be eddy currents generatedin the inductor 2! which, due to thestated magnetomotive reactions, willaccelerate inductor 2 I. At the same time, the magnetic field will drawin magnetic grease from the ridges in spaces 29 into the gap C, causingthe gap to be filled even against plowing-out action of the plows 3|. Ifthe coil 5 is sufficiently excited, there will finaly occur a magneticstiffening of the grease with complete synchronism between the drivingand driven elements, the magnetic grease in the gap C acting as a staticmagnetic and frictional interlock. It will be seen that as synchronismis approached, the relative motions ofthe plows with respect to theinductor 2! become less, so that the mechanical efficiency of plowing isreduced until ultimately at synchronism there will be no plowing-outeflect whatever. The clutch is then looked at 1:1 synchronous movementof the driving and driven elements.

ing action decreases to allow said slip. Immediately the plows assume arelative motion to the inductor and tend to sweep out grease from thegap. At some stage in the reduction of the magnetic field (near zerovalue) most'of the grease is swept out and the nondrag-idlingconditionsare resumed with a maximum amount of grease in thechannels!!! (Figs. 1 and 3), a small amount being left in the gap' C,'asillustrated in Fig. 1.

It should he remarked in connection. with deenergizing the "coil 5, thatthe band of nonmagnetic material H' in the toroidal magnetic circlearound the coil 5 accelerates decay of" the flux, so as to minimize theresidual magnetism carried in the grease. Thus-it more quickly slumpsand is' plowed out.

It is not necessary to plow all of theg'rease out of the gap C, and forthis reason the height of theplows 3i is only a fraction of the gapwidth, for example, one-half of the gap width,

or in the present example,.010 inch. This pro-- substantial amount takeup a position between the poles where it might be excessively churned.Thus it is unnecessary to close the spaces between poles. That is tosay, the polar field member may present tooth-like irregularities towardthe inner surface of the inductor drum 2i without undue resultingchurning. It should be noted also that the centrifugal force of thegrease in the drum 2i normally biases it toward leaving the gap. Thus ifthe amount of grease introduced is not excessive, it is possible at alltimes-to plow in an air gap between the poles l3 and inductor 2!, aidedby the outslinging bias. i

In Figs. 4-6 is shown another form of themvention in which like numeralsdesignate like parts, so far as applicable. In this case," automaticscrapers are used which are 'movable'rela- 'tiv'elyto the field member.

' Two opposite ones of these are suflicient. Only one will be described,since both are identical. One is sufficient 'if dynamic balance isunimportant, .as on slowspeed machines. In this case, coaxial pivot pins-33 are provided in the bases of :two adjacent poles I3. These pivot :arocker frame shown generally at 35. This rocker framehas side plates 31connected atone end by means of V-shaped plowingout portion 39. At theotherend, plates 37 :are connected by a bar H, the ends of which areformed as plowing-in portions 43. Depressed grooves 45 are provided inthe inductor 21 in planes lateral to the plane of rotation of the polesl3. These accommodate the plows 43, which are also operative in thestated lateral planes.

Referring again to the frame 35, the rear bar 4.! thereof carriescounterweights 41. adapted to e'fiect equilibrium around pivot pins 33.The parts 31, 39, ll, 43 and 4! are composed of nonmagnetic materialsuch as stainless steel. Welded to the underside of the forward plow 39is a magnetic slug 49, which reacts to any magnetic'field generated bythe coil to be pulled in toward the center of rotation. Springs 5-!reacting from the bottoms of sockets 53 in the rings 1 and 9, biasoutward the out-plowing portion 39. The weights of these are taken intoconsideration in determining the equilibrium above mentioned. Inwardmovement of in-plowing plows 43 under bias of springs 51 is limited bypin stops 55, as is also the outward movement of plow 39. If themagnetic slug 49 be drawn in, a pin stop 57 limits the inward movementof the out-plowing plow 39 and the outward movement of the in-plowingmembers 43. The pin stops 55 and 51 are so arranged that either plow 39or plows 33 move from respective positions inside of the cylinder,defining theends of the poles 13 to positions about .010 inch outsidethereof and in the approximately .020 inch gap C, without touching theinner face of the inductor 2 l. The masses of the movable pivot parts onopposite sides of the center lines of pivot pins 33 being such astocounterbalance one another against centrifugal forces, the action ofthe plow member 35 is under control of the magnetic s1ug 49 actingagainst the springs 5|.

Operation of theform of the invention shown in Figs. 4-6 is as follows,assuming the driving member I to be rotating relatively to the inductor2| in the directionillustratedby the arrow in Fig. 6, the coil 5 beingdeenergized:

The springs 5| push .out the out-plowing member 39 which plows thegreasefrom the inductor surfaces and into the channels '45. Uponexciting the coil 5, the slug 49 is drawn inward against the action ofsprings 5|, thus drawing in the plow 39 and pushing the .in-plowingmembers 43 into the grooves 45. The magnetic grease is thus plowedinward from the grooves into the gapv C, the action beingaugmented bythe attraction of the grease into the gap caused by the magnetic fieldin the gap. Otherwise the action is the same as that alreadydescribed'in connection with the form of the invention shown in Fig.1-3. However, in the case of the construction of Figs. 4-6, theout-plowing and ii -plowing members 35 and 3, respectively, areautomatically positioned in response to field excitation, making bothin-plowing and out-plowing actions positive and coordinated with clutchclosing (energizing) and releasing (deenergizing). operations. In Figs.4-6 the parts are in deenergized releasing positions.

.LIII Figs. 7-9 is shown-a form of the invention "which will.operatewsimilarlylin either direction of :relativemotion;:betweemthemembers .3 and 1:5 Like numerals adesignatenlike partswhere applicable. J Inthis-case, each .plow assembly is composed of:side arms .59, pivoted tothe field :membenat pins 61-. Extrav space isleft between two of the poles l3 to accommodate 'adiamondshapeddouble-ended plowing-out portion havingoppositely directed V-shapes orchevrons "63 and-65. Weldedto the .bottom 'of these is a magnetic slug161. Springs 6B bias outwardthe portions-3, 165, 67, the movement beinglimited by pin stop 13L Inward" movement of the plows 6.3 and65islimited'by pin s'tops13 Theopposite ends of :theside bars 59 arejoined by oppositely concave plows 15 and 11, joined centrally at 19 andprovided with ofi -set portions 8| for entering the 'gro'oves 45.

.Movement of the rotary field-carrying mem- -ber 31in the directionshown by the solid arrow in .Fig. 9, relativeto the member l5, resultsin the same type of operation already described in the form of theinvention shown in Figs. 4-6. In this case, the operative outplowing'element is 63 and the operative in-plowing elm'ent is 11. On theother band, should the member I 5 overrun the movement of member3,'becom'ing the driver, as sh'own'by the dotted arrow in Fig. 9, thenthe out-plowingportion '65 and the in-plowing portion :15 be'c'omeeffective. Otherwise the operation is the same as alrea y made clear.Inthis modification the in-plowin'g' portions 15 and 71 are continuouslyconcave downto the central engaging portion "l9, so that the in plowingcomponent of action when initiated is effective across the entire innerface-of theinductor 2|. As before, the rocking assembly of parts formingthe plows is counterbalanced in response to centrifu al'force.

This form of the invention, provides not only forallowing either or |5tobe. the driver under a given direction of rotation, but when either .Ior lfiispdriving, theirotationis reversible, without losing the desiredplowingact'ionsr I In Figs. 10-12 is shownanother modification whichissimilar to that shown in Figs. 7-9.

designating Ilike .parts where ap- In this case there is substituted fortinuous magnetic rings :83fand 85, which are inn 81 and 89 only enoughto accommodate the'motionsiof .the opposite ends of the rocking plows.These rings peripherally overlap the coil 5, as indicated at 90.Operationsofar as the plow is concerned is the same as "alreadydescribed in connection with Figs. 7-9. However, this type of clutch,essentially having no discontinuities in the toroidalfield sweeping. themember 21, will not generate "eddy currents in this member. This iswitht'he slight exception "of the few stray eddy currents producedbecause of the interruptions 81 and 8-9, but these are insignificant.Thus in this form of the invention the entire coupling action when themagnetic grease is drawn and plowed into the gap C'is due to themagneto-frictional eiTect or resistance to shear afforded by anymagnetic grease in thegap 0.- Under partial excitation of the coil,"there will be subst'antial'slip, and as the excitation is increased,the magnetic greasest'iffens until synchronism is reached, in whichcontingency the 'driving'and driven members are locked together. Sincethe type of plow shown'in I3, adjacent the C011 .5, a pair of -con'cessive churning action.

Figs. 10-12 is functionally the same as that shown in Figs. 7-49,'1',SOfar as plowing action. is concerned, no further description is needed,similar but primed reference .:characters indicating plow partsobviously operating similarly to the plow parts of Figs. 7-9. As in thecase of Figs. 7-9, either member 5101' 15 may be the driving or drivenmember.

In the forms of the invention shown in Figs. 4-12, .the plows arepermitted to move out only partially into the magnetic gap C. It isclear that they-could be allowed to move out against the inner face ofthe inductor 2|. The former action is preferable from the view point ofquiethowever, is preferable since the maximum travel T of the materialis reduced to one-half.

In view of the above, it will be seen that several advantages accruefrom the invention. First, a practically nondrag idling action occursbetween the driving and driven members when the coil 5 is deenergized.Second, the magnetic fluid being a semisolid, never runs to the bottomof the container afforded by the inductor 2|, so that the apparatus isin just as dynamically balanced a condition when starting as at anyother time. Apparatus employing a magnetic liquid has an initialout-of-balance, condition until the liquid is spread evenly bycentrifugal force. Moreover, in the case of a semisolid matrix, magneticparticles in the containing semisolid do not tend to settle out of thematrix. In a magnetic liquid employing finely divided metallic particlesthere is a settling action during long periods of rest of the apparatus.It is sometimes necessary to break loose a fairly solidified-mass ofsettled-out metal particles in the bottom of the inductor when a liquidmatrix is used.- This is not true in the case of the semisolid matrixused herein, since it maintains its position at all times around theinductor 2!.

Another feature is that since the magnetic semisolid holds its positionon the inside of the member 21 and outside of the central portion, thepoles do not need to be encased or provided with nonmagnetic fillerbetween them, as is desirable to prevent churning in the case of amagnetic liquid. The only churning encountered in the case of thepresent invention is inconsequential and occurs only during shortintervals of plow action. Thus the magnetic semisolid will be of a morestable nature than a magnetic liquid, partly because it is not subjectedto the ex- It may also be observed that a magnetic grease is much easierto retain between two rotary members by means of ordinary seals than isa magnetic liquid.

The plows contribute advantages which may be used without semisolidmagnetic material. For example, if magnetic liquid likefiowable'material such as specified in U. S. Patent 2,525,571 issubstituted for the magnetic semisolid, the use of plows helps quicklyto distribute the liquid and will aid in breaking any sedimentation or"such material as above described. 'The plows are also useful inconnection-with magnetic fiowable ma- 5 terial of the dry powder typesuch as described in U. S. Patent 2,519,446 since they prevent anypacking oi.such material from interfering with clutch release.

It will be understood that the threshold excitation of the field memberfor operating the movable plow may be any necessary value. In the claimsthat follow, any value of excitation above the threshold value isreferred to as substantial excitation. Values below this may beunderstood to correspond to a substantially unexcited condition.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

We claim:

1. A dynamoelectric machine comprising relatively rotary field andmagnetic members, one being inside the other which forms a cylindriccompartment, a magnetic semisolid mixture carried in said compartment,one member comprising an annular field coil and adjacent polarizingrings forming a gap relative to the magnetic member into and from whichthe semisolid mixture may move, and a pivoted scraper on one of themembers movable between positions in and out of said gap.

2. A dynamoelectric machine comprising relatively rotary field andmagnetic members, the former being inside of the latter which forms acylindric compartment, a magnetic semisolid mixture carried in saidcompartment, the field member comprising an annular field coil andadjacent polarizing rings forming a gap relative to the magnetic memberinto and from which the semisolid mixture may move, and a pivotedscraper on the field member movable between positions in and out of saidgap.

3. A dynamoelectric machine comprising a field member and an adjacentmagnetic mem ber spacedtherefrom by an annular magnetic gap, saidmembers being relatively rotary, one of said members being outside ofthe other and forming an annular container, a mixture composed of asemisolid grease-like substance and magnetic particles dispersedtherethrough located in said container and movable into a position in orout of said gap, and an angled plow extending into said gap adapted uponrelative movement between the field and magnetic members to move saidmixture laterally with respect to the gap.

4. A dynamcelectric machine comprising relatively rotary field andmagnetic members having a gap therebetween, the magnetic member beingoutside of the field member and forming a cylindric compartment, amagnetic semisolid mixture in said compartment, and a plow movablymounted upon the inner field member to take up a position either out ofthe gap or extending partially across it, said plow incorporating amagnetic element responsive to a magnetic field generated in the fieldmember to be drawn completely out of the gap.

5. A dynamcelectric machine comprising relatively rotary field andmagnetic members having a gap therebetween, oneof said members beingoutside of the other and forming a cylindric compartment, a magneticsemisolid mixture in said compartment, and a plow movably mounted uponthe inner member to'take up a position either in.

or out of thegap, said plow incorporating a mag-.-

netic element responsive-to a magnetic field gen-1 erate'dinithe fieldmember to be drawn out of the gap;

'6. A dynamoelectric machine comprising rela-' tively rotary field andmagnetic members hav ing, a gap .therebetween, one of said members beingoutside of the other and forming a. cylindric compartmenta magneticsemisolid mixture in said compartment, a plow movably mounted upon theinner member to take up a position either in orvout of the gap, andmeans normally biasing outside of the other and: forming a cylindriccompartment, a magneticsemis'olid mixture in said compartment, a rockermounted uponthe inner member and having an iii-plowing plow at one endand an outeplowing'plow at the other end each plow being adapted to.take up positions to plow said mixture either into or out of the gap,,andmeans normally biasing the rocker to one position,.said rockerincorporating a'mag=- netic element responsive to substantialexcitationof the field member to be moved toits other posi tion; V

8. A dynamoele'ctric machine comprising relatively. rotary field andmagnetic members hav= ing 'a gap therebetween, one of said members beingoutside of the other and forming a cylindric compartment including areceptiverecess on one side of the gap, amixture composed of 8.1881111?-solid greaseelike substance and magnetic particles dispersedtherethrough. in said compart= ment movable to andzf-rom the-gapandrecess, and a rocker movably mounted upon the inner meme bar andicarrying an out-eplowingiplowfor cooperation'with said mixture in thegap vand an in v plowing plow for cooperation with said mixture in therecess, said'rocker incorporating an e1e= ment responsive to substantialexcitation of; the field member to. draw the outepl'o'wing element outofthe gap and'to move the in-plowing. plow into the recess. c

- 9 A dyna'moeleetri machine'comprising relatively rotary field andmagnetic members hav ing' a gap therebetween, one ofisaid members beingoutside of the other and forming. acylindric compartment including areceptive recess onione side ofrthe gap, a magnetic semisolid mixturein.

said'compartment, anda rocker movably mounts.

ed'upon' the inner member andcarryihg an out plowing element forcooperation with the' gap and an insplowing element for cooperation withthe 'recess, said rocker incorporating an element responsive tosubstantialexoitation of the field member tomove so as to draw theout=plowing element out of the gap andto move the in'-'-p1ow= ingelement into the recess,-both the out-plowing and'implowing elementshaving oppositely slopping portions efiectivie to perform the outplowing and iii-plowing functions relative to the gap re spectivelyregardless of the relative motions or the rotary members.

10. h-oynamoeiectne machine comprising relatively rotary fieldand'magnetic members having a gap therebetween, one of said membersbeing outside of the other and forminga cylindric compartment includingspa e ono esidet e; a magnetic, semisolidxmixturea n co a trn nt, and.a; rock r, morably' mount d; .unon; the inner member andcarryinganoutplowing; element for cooperation with, thegap and'an'inr-lplowing element. for coopera ion; Withe he'sna K said rockerincorporating annelement, resppn to, substantial excitation of the;field; membe r to. move so as to actuate, theout-plowing element out, ofthe gap and to actuate theiinrp ow n element into, thegspaca v ,5 1,1,.Adyn moeleotrie machin ;eomprisingrelan; tively rotary field andmagnetic members;;.ha ing, a gap; therebetweem. o e ofv saidflmembersjbeing outside of the other and tannin acrl'mdriei; compartment includingspace on opposite sides: of the. ap, a ma netic semisolid mixture in;said compartmentand arocker movablr mou ed upon the; inner member;- and;carrying a; V;- shaped out-plowing element for dobperationwith the gap.and V-shap.ed, in plowingelements for; cooperation with said, space and;the: gap, said: rocker incorporating an element responsivegiosubstantial excitationoflthefield membertomove; so as to drawtheout-plowing element out of the gap and to move theinsplowingelementsintothe; gap, 'saidrocker being substantially" dynamic'ai ilyi balanced inrespect to centrifugal;foreesthereon; 12;. Avdynamoelectricmachinecomprising relatively rotary field and" magneticmembers haivg ing agap therebetween; one, of, said/members! beingoutside of the-other and forming aicylindrie; compartment including a,receptive recess: on one; side of the gap, a.magneticsemisolid'mixtureiin said compartment, and a;rockergmovablyzmountg. ed upon the inner member; and,carryinganflelee-fl. merit for outeplofwing cooperation withztheigarhand an element forineplowing cooperation: with the recess, said rockerincorporatinganielement,v responsive to substantial excitation-of theholdmember tov move so as .to draw the out-plowing:- elernent out of thegap 'to stop, outeplowingendz to. move the in-plowin'g elementintothezreeess: to effect in-plowing, both, the outeplowingami:in-plowing elements. having, oppositell! sloping portions efiective.toznerfofrm theout-plowine and; iiilowing functions respectively;regard-1eso;v of;v the relativemotions of -thie;rotary m mbers; I 13. Adynamoeleotric'machine comprisingrelai; tively rotary field andmagnetiotII.I :mixers,v the;- former being inside-of the ilattertsaid'latter-forme ing a cylindric. compartment, magneticisemiru solidmixture vcarried in said'compartment; thefield member comprising anannularfieldpoilg and-adjacent polarizing:ringsiformingoazsa B18121.tive tothe magnetic member into; andfrom-zwhichtc the semisolid mixturemay move; a: pivoted: plow; on the field membermovab1e:-betweenpositions; in and out ofsaid gap, an elementgbiasingitheplow nder substantially deener lzedr ondi ion of the field coil to.takes-1m positionwithin' h 1 p, and amagnetic memhor'ontheplow .o. J.siveto-substantial' excitation pfthe. fiel r o a ainst s i b as. to; caueshe ol wels imr a positionu s de of lie'sa t A dvn mo l i m chine,coomnr s fie dember nd: a r la i e y r tary: dlo. magnetic member spacedtherefrom -byia we ing magnet c ap eaoh' avir e .:a orle '-fo ing n encs ambercon a n sale-s d n rm lly enfmtr sha aqie h a a cli g g w lemee imat ri we id o m mb rw pl w; e eamo ably mounted on n oisa dmtmb f-a idnmally biased when the field member is substantially unexcited to extendfrom the working periphery of its supporting member and to plow at leastsome of said material out of the gap into-said space and responsive tosubstantial excitation of said field member to plow said materialintothe gap from said space, the plowing actions being responsive to certainrelative movements between saidmembers.

l5.- A dynamoelectric machine comprising a field member and a relativelyrotary adjacent magnetic member spaced thereiromby a working magneticgap, eachhaving a working periphery defining the gap, one of saidmembers formin'g anenclosing chamber containing the gap and a normallyempty space adjacent the gap, a clinging fiowable magnetic materiallocated between said rotary members, and a double-acting plow devicemovably mounted on one of said members and normally biased when thefield member is substantially unexcited to extend from the periphery ofsaid member and to plow at least some of said material out of the gapinto said space and responsive to substantial excitation of said fieldmember to plow material into the gap from said space, the stated plowingactions being effective in accordance with the directions of therelative movements of said members.

16. A dynamoelectric machine comprising a field member and a surroundingmagnetic member spaced therefrom by a working magnetic gap and forming achamber containing said gap and a normally empty space adjacent the gap,each member having a working periphery adjacent the gap, said membersbeing relatively rotary on a common axis, a fiowable magnetic materiallocated between said rotary members, and a plow attached to the fieldmember and extending from its periphery and at an angle relative to saidaxis, which plow extends into the gap to plow at least some of thematerial therefrom into said space when the field member is ole-excited,to provide an air gap between the spaced peripheries of the rotarymembers. a

a 17. A dynamoelectric machine comprising a field member and an adjacentmagnetic member spaced therefrom by a peripheral working magnetic gap,each member having a working periphery adjacent the gap, said membersbeing relatively rotary and one of them forming a chamber containing thegap and a space adjacent the gap, a fiowable magnetic material locatedbetween said rotary members, and a plow extending from the periphery ofone member and into the gap and adapted upon relativemovement of the onemember with respect to the other to plow at least some of said materialfrom the gap into said adjacent space to provide an air gap between thespaced peripheries of the rotary members.

18L'A dynamoelectric machine comprising an inner polar field memberthe'periphery of which is essentially circular and an outer adjacentessentially circular magnetic member spaced therefrom by a peripheralworking magnetic gap and forming a container whichincludes the gap andaspace adjacent the gap, said members being relatively rotary, afiowable magnetic material located between said rotary members and contained in the outer one, and a plow extending from the polar peripheryof the inner field memher into the gap and adapted upon relativemovemerit of one member with respect to the other to plow at least someof said material from the gap into said space to provide an air gapbetween the relatively rotary members.

19. A dynamoelectric machine comprising a field member and an adjacentmagnetic member spaced therefrom by a peripheral working magnetic gap,each member having a working periphery adjacent the gap, said membersbeing relatively rotary and one of them forming a chamber containing thegap and a space adjacent the gap, a fiowable magnetic material locatedbe tween said rotary members, and a chevron-shaped plow carried by onemember and pointed in one direction and adapted upon relative movementof the last-mentioned member in said direction with respect to the othermember to plow said material from the gap into said space, said plowextending from the working periphery of the member upon which it ismounted.

20. A dynamcelectric machine comprising an essentially circular magneticfield member and an. adjacent circular magnetic member spaced therefromby a working magnetic gap, each member having a working peripheryadjacent the gap, said members being relatively rotary and one forming acontainer around the other including the gap and a space adjacent thegap, a mixture adapted to cling to the surfaces of the members withoutgravitating therefrom and composed of a semisolid grease-like substanceand magnetic particles dispersed therethrough, said mixture beinglocated between said members and adapted to stiffen and close the gap soas to synchronize the members when the field member is sumcientlyvexcited, and plow means attached to and extending beyond the workingperiphery of one of said relatively rotary members and extending intothe gap defined by said members, said plow means subtending a limitedpart of the periphery of the member from which it extends, whereby upontie-excitation of the field member and relative movement between themembers said plow will plow the mixture out of the gap into saidadjacent space to form a circular space between the mixture and theworking periphery of the member to which the plow is attached.

- 21. A dynamoelectric machine comprising a magnetic and essentiallycylindric field member and an adjacent cylindric magnetic member spacedtherefrom by an essentially cylindric gap, said members being relativelyrotary, one of said cylindric members being inside of the other, saidother member forming a container including the gap and a space adjacentthe gap, a mixture adapted to cling to the surfaces of either memberwithout gravitating therefrom and composed of a semisolid grease-likesubstance and magnetic particles dispersed therethrough, said mixturebeing located between said members and adapted to stiiien and close thegap so as to synchronize the members when the field member issufiiciently excited, and plow means attached to and extending beyondthe periphery of the one of said cylindric members which is inside theother and extending outward into the cylindric gap defined by themembers and subtending a limited part of the peripheral extent of thegap, whereby upon de-excitation of the field member and relativemovement between the members said plow means will plow the mixture outof the gap into said adjacent space to provide a cylindric space betweenthe inner member and the mixture clinging to the outer member.

MARTIN P. WINTHER. RALPH L. JAESCHKE.

(References on following page) The following references are of record inthe file of this patent:

UNITED STATES PATENTS Number Name Date 811,654 Murphy Feb. 6, 19061,927,616 Rudquist Sept. 19, 1933 2,398,638 Hedtel Apr. 16, 1946 14 NameDate Winther Oct. 10, 1950 OTHER, REFERENCES I Raymond EngineeringLaboratory Report, September 17, 1948.

National Bureau of Standards Technical Report 1213. (Received inDivision 68 on March 30, 1948.)

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